WASHINGTON — A growing number of Texans are seeking treatment for methamphetamine addiction, reversing a downward trend in abuse in the state since a 2006 federal law banned over-the-counter sales of medicine containing the synthetic drug pseudoephedrine.

Last year 6,219 Texans sought substance abuse treatment for methamphetamine and amphetamine addiction, up 590 from the previous year, according to the Treatment Episode Survey data from the federal Substance Abuse and Mental Health Services Administration.

In 2014, 15.8 percent of people seeking addiction help in Texas listed amphetamines as the primary drug of abuse. Both the number of people in treatment and the percent of people seeking help for the drug were higher last year than in 2006, when the law meant to curb methamphetamine abuse was passed.

“We’re in the middle of a methamphetamine epidemic,” said Jane Maxwell, research director at the University of Texas at Austin’s School of Social Work, who released a report last month on methamphetamine use in Texas.

Treatment Episode Survey data for 2013 and 2014 is not yet available for all states, but experts say a national household survey that measures methamphetamine use nationally hasn’t indicated much change in recent years.

“Even though it doesn’t look like a huge problem nationally, it’s a very big problem in some areas,” said Dr. Mary-Lynn Brecht, an adjunct professor at the University of California, Los Angeles, who studies methamphetamine.

Methamphetamine, chemically similar to amphetamine used in attention deficit disorder medication, is a synthetic, highly addictive drug that acts as a stimulant. The drug’s crystal form can be concocted in a lab, while weaker meth recipes can be made in car trunks and one-liter bottles. Methamphetamine users smoke, snort and inject the drug.